1. Field of the Invention
The present invention generally relates to an electronic endoscope apparatus for displaying an interior image of a biological body under medical examination by utilizing an image scanner with a light source. More specifically, the present invention is directed to an electronic endoscope apparatus employing an automatic light source controller to automatically turn OFF a light source when an endoscope examination is completed, or interrupted for a predetermined duration time.
2. Description of the Related Art
A conventional electronic endoscope apparatus is arranged with the following construction to observe an interior portion of a biological body for a medical purpose.
A specific interior portion within the biological body is illuminated by illumination light. The light is emitted from a light source such as a xenon lamp mounted on the electronic endoscope apparatus, and transferred via a light guide, made of, for instance, an optical fiber, to a distal end of a scope.
A solid-state imaging element, e.g., a charge-coupled device (referred to as a "CCD"), similarly mounted on the distal end of the scope, receives light reflected from the specific illuminated interior portion, and thereafter converts the reflected light image of the specific interior portion into a corresponding image signal. The image signal is further converted by a camera control unit (referred to as a "CCU") into a video signal.
The video signal is then processed in a video signal processing circuit and/or a digital scan converter (referred to as a "DSC") for the image reconstruction process, and thereafter displayed on a CRT monitor.
All of the above-described functions are under control of a central processing unit (referred to as a "CPU").
In the conventional electronic endoscope apparatuses, to turn off the light source, an operator must manipulate a light source switch. In other words, the light source is manually controlled in the conventional electronic endoscope apparatus. As a result, a xenon lamp, or other types lamps forming of the light source remains turned-ON even after the endoscope diagnostic operation is completed.
In this case, since the lighting duration time of the xenon lamp or the like directly an influences the life thereof, there is a problem that the life time is furthermore shortened while the lamp is turned ON even after the endoscope diagnostic operation.
In addition, it is known that according to the brightness characteristics of a xenon lamp, the brightness is conspicuously lowered within a relatively short duration time since a new xenon lamp is turned ON.
Therefore, in case that a xenon lamp is employed in the light source of the electronic endoscope apparatus, unnecessary lighting time period must be reduced as shortly as possible.
On the other hand, the lamp power consumption is relatively large, as compared with the total power consumption of the electronic endoscope apparatus. Accordingly, unnecessary lighting of the lamp causes higher power cost of the electronic endoscope apparatus.